JP3436486B2 - Ultrasonic vibrator and manufacturing method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic vibrator and a manufacturing method thereof, and more particularly to an ultrasonic vibrator and a manufacturing method for improving an ultrasonic beam focusing method.

[0002]

2. Description of the Related Art An ultrasonic diagnostic apparatus for observing a living body by transmitting and receiving ultrasonic waves to and from a living body, which is a subject, is widely used. The ultrasonic transducer used in the ultrasonic probe connected to the diagnostic device generally has a laminated structure. For example, focusing on the piezoelectric vibrator that actually generates ultrasonic waves,
A backing material is disposed on the rear surface of the back surface for mechanical damping to widen the frequency band. on the other hand,
Two matching layers corresponding to λ / 4 are arranged on the front surface of the piezoelectric diaphragm. The matching layer, by matching the acoustic impedance of the piezoelectric diaphragm or the like, and the acoustic impedance of the living body that is the subject,
The transmission of ultrasonic waves is improved. A plurality of electrodes are formed on the front surface and the back surface of the piezoelectric vibrating plate. For example, a minus lead wire (flexible cable if necessary) is connected to the front surface side and a plus lead wire (necessary to the back surface side). Flexible cable) according to
A predetermined voltage is applied to the front and back surfaces of the piezoelectric vibrating plate to transmit an ultrasonic wave, and at the same time, a signal is transmitted by a reflected wave reflected by a living body or the like.

By the way, when transmitting and receiving an ultrasonic beam by the ultrasonic transducer, it is necessary to focus the ultrasonic beam. In this case, focusing in the array direction of the vibrating elements that make up the piezoelectric vibrating plate is performed by delaying the transmission wave applied to each transducer during transmission and delaying the reception wave of each transducer during reception. By doing (electronic focus). On the other hand, focusing of the ultrasonic beam in the direction orthogonal to the array direction of the vibrating elements uses an acoustic lens to form a focus at a predetermined position to improve the resolution in the direction perpendicular to the electronic scanning direction. Since the acoustic lens directly contacts the living body, the acoustic lens has a convex shape in order to maintain the close contact with the living body.
In this case, the speed of sound in the living body is about 1530 m / sec,
The material of the acoustic lens needs to have a speed of sound slower than that of a living body. Generally, a silicone rubber having a sound velocity of about 1000 m / sec is used.

[0004]

However, the acoustic lens using silicone rubber has a large temperature dependence of the sound velocity,
There is a problem that the focus position varies depending on the usage environment. Further, the acoustic lens made of silicone rubber has a problem that attenuation at high frequencies is large. This attenuation tends to increase particularly toward the central portion of the acoustic lens, and there is a problem that the ultrasonic beam characteristics are deteriorated, and the original performance of the ultrasonic transducer cannot be fully exhibited.

On the other hand, instead of using the acoustic lens, when the surface of the vibrator is formed into a concave surface having a curvature, the connection between the electrode of the vibration element and the extraction lead becomes difficult in terms of shape. There is.

The present invention has been made to solve the above problems, and an object thereof is to focus an ultrasonic beam and form a focus without using an acoustic lens having the above problem. An object of the present invention is to provide an ultrasonic transducer and a manufacturing method thereof.

[0007]

In order to achieve the above-mentioned object, the structure of the present invention comprises a hard backing material having an upper surface having a predetermined curvature in a direction orthogonal to the scanning direction of ultrasonic waves. On the top surface, it functions as a signal lead thin plate.
A sheet-shaped first flexible cable, a plurality of notched grooves parallel to the scanning direction are formed in a direction orthogonal to the ultrasonic scanning direction, and at least one of the front and back surfaces is divided; Functions as a thin sheet of ground lead
A sheet-like second flexible cable, a laminating step of forming a laminated by stacking and one layer of the matching layer, sequentially body, the pressure from above or below the laminate addition to, the
First flexible cable and second flexible cable
With the piezoelectric diaphragm sandwiched between the front and back
Then, a deformation step of pressing and deforming the laminated body into a shape along the upper surface shape of the backing material is included.

Here, the piezoelectric vibrating plate has a plurality of vibrating elements arranged in a scanning direction, and the backing material has a predetermined curvature in a direction orthogonal to the arrangement direction. Further, the first flexible cable and the second flexible cable are connected to a piezoelectric vibrating plate to apply a drive voltage to the piezoelectric vibrating plate and send a signal by the received reflected ultrasonic beam.

According to this structure, since the piezoelectric vibrating plate and the matching layer are pressed and formed in a shape corresponding to the curved surface of the backing material, the ultrasonic beam transmitted and received from the piezoelectric vibrating plate is directed in the direction corresponding to the curvature. Can be focused. Also,
Since the laminated body is pressed and deformed while the piezoelectric vibrating plate is sandwiched by the sheet-shaped first and second flexible cables, it is possible to easily connect the bending piezoelectric vibrating plate and each flexible cable.

In order to achieve the above-mentioned object, in the structure of the present invention, in the manufacturing method, the deforming step includes
It is characterized in that the laminated body is pressed and deformed by a pressing plate having a pressing surface having a shape corresponding to the upper surface shape of the backing material.

According to this structure, the laminate can be easily pressed and deformed by a uniform pressing force.

In order to achieve the above-mentioned object, the structure of the present invention is the manufacturing method, wherein between the electrodes of one of the two surfaces of the first flexible cable and the piezoelectric vibrating plate and between the second flexible cable and the piezoelectric vibrating plate. It is characterized in that the connection between the other electrodes of the two surfaces of the plate is performed at the same time as the pressing deformation of the laminate.

According to this structure, the electrode connecting work can be performed easily and quickly.

In order to achieve the above-mentioned object, the structure of the present invention further comprises the step of interposing an adhesive between the backing material and the laminate, and between the laminates, and the modification. And a curing step of curing the adhesive while maintaining the pressed state of the step.

According to this structure, the ultrasonic transducer having the laminate having the shape corresponding to the curved surface of the backing material can be easily manufactured by a series of continuous manufacturing steps.

In order to achieve the above-mentioned object, the structure of the present invention is, in the manufacturing method, a groove forming step of forming a groove in the laminate for dividing into arrayed vibrators after the curing step. It is characterized by including.

According to this structure, it is possible to easily form an array type vibrator including wiring and the like.

In order to achieve the above object, the structure of the present invention has a hard backing material having an upper surface having a predetermined curvature in a direction orthogonal to the scanning direction of ultrasonic waves, and an upper surface of the backing material. A bendable piezoelectric vibrating plate in which a plurality of notched grooves parallel to the scanning direction are formed in a direction orthogonal to the scanning direction of the ultrasonic wave in order to bend along the shape, and at least one of the front and back surfaces is divided. And one or more matching layers curved along the curved shape of the piezoelectric vibration plate,
The front surface and the back surface of the piezoelectric diaphragm include the piezoelectric diaphragm.
Sandwiching the signal lead thin plate and ground lead thin
A sheet-shaped flexible cable that functions as a plate is closely arranged.

According to this structure, the ultrasonic beam transmitted and received from the piezoelectric vibrating plate can be focused in the direction according to the curvature. Further, since the laminated body is pressed and deformed while the piezoelectric vibrating plate is sandwiched by the sheet-shaped first and second flexible cables, it is possible to easily connect the bending piezoelectric vibrating plate and each flexible cable.

In order to achieve the above object, the structure of the present invention is such that, in the vibrator, the piezoelectric diaphragm and
A groove is formed in the matching layer to form an array vibrator.

According to this structure, it is possible to easily form an array type vibrator including wiring and the like.

In order to achieve the above-mentioned object, the constitution of the present invention is characterized in that the cutout groove is filled with an adhesive having flexibility after being hardened .

According to this structure, it is possible to obtain a curved shape while maintaining the strength of the piezoelectric vibrating plate in which the notch groove is formed.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention (hereinafter referred to as an embodiment) will be described below with reference to the drawings. FIG. 1 shows a state in which the ultrasonic transducer 10 of this embodiment is deformed by pressing.

First, the structure of the ultrasonic transducer 10 will be described. In the case of the present embodiment, the ultrasonic transducer 10 includes the first flexible cable 14, the piezoelectric vibrating plate 16, the second flexible cable 18, the first matching layer 20, on the backing material 12 having the concave curved upper surface. The second matching layer 22 and the second matching layer 22 are sequentially laminated to form a laminated body 24, and a thermosetting adhesive is interposed between the respective members. In the case of this embodiment, an example having a double matching layer will be described, but the number of matching layers can be arbitrarily changed.

The backing material 12 is made of, for example, a hard material mainly made of epoxy resin and mixed with metal such as tungsten, and the curved surface of the upper surface is in the scanning direction of the ultrasonic beam transmitted and received by the piezoelectric vibrating plate 16. In the orthogonal direction, a concave surface is formed with a predetermined curvature (for example, radius of curvature 20 mm; curvature ≈ focal length). The backing material 12 has the function of widening the frequency band by mechanically damping the ultrasonic vibration from the piezoelectric vibrating plate 16 on the back surface side of the piezoelectric vibrating plate 16.

On the concave curved surface of the backing material 12,
A first flexible cable 14 made of a thin sheet-shaped flexible wiring board is arranged and can be connected to a single or a plurality of electrodes (not shown) formed on the lower surface side of the piezoelectric vibrating plate 16. Similarly, a single or a plurality of electrodes (not shown) are formed on the piezoelectric vibrating plate 16 so that the second flexible cable 18 can be connected (when connecting to a single electrode, an adhesive agent will be described later). After curing, can be cut by grooving and divided into elements). In the case of this embodiment, the first flexible cable 14 functions as a signal lead thin plate, and
The flexible cable 18 functions as a ground lead thin plate, applies a predetermined drive voltage to the piezoelectric vibrating plate 16, and sends a signal based on the ultrasonic beam reflected by the living body to an ultrasonic diagnostic apparatus (not shown).

The piezoelectric vibrating plate 16 may be a single-type vibrating element or an array type in which a plurality of vibrating elements are arranged in an array. In the present embodiment, the ultrasonic beam in the vibrating element arrangement direction is controlled by delay control. An array type vibration element capable of focusing is described as an example. As shown in FIG. 2A, the piezoelectric vibrating plate 16 has a plurality of strip-shaped vibrating elements 16 arranged in the direction of arrow A in the figure.
It is formed from a. Then, by delaying the transmission / reception wave of each vibrating element 16a, it is possible to perform focusing in the arrow A direction.

The piezoelectric vibrating plate 16 used in this embodiment is
As shown in FIG. 2A, a plurality of cutout grooves 2 are formed in a direction (arrow B direction in the drawing) orthogonal to the array direction of the vibration elements 16a.
6 is formed, and by applying an external force from the direction of arrow C in the figure, it can be bent as shown in FIG. 2 (b). At this time, strength can be maintained by filling the notch groove 26 with an adhesive such as silicone rubber that can maintain flexibility even when cured. Note that FIG.
2B shows a state in which the state of FIG. 2A is turned upside down and curved. A composite piezoelectric material can also be used as the piezoelectric vibrating plate 16.

Further, the second flexible cable 1
On the upper surface of 8, a first matching layer 20 having a thickness of λ / 4,
The second matching layer 22 is provided to match the acoustic impedance of the piezoelectric vibrating plate 16 and the acoustic impedance of the living body, which is the subject, to improve the transmissibility of ultrasonic waves.

Next, a method of manufacturing the ultrasonic vibrator 10 made of the above-mentioned components will be described.

First, the backing material 12 is placed on a fixing jig or the like (not shown), and an adhesive (for example,
Apply a thermosetting adhesive). Subsequently, the first flexible cable 14 is laminated, and an adhesive is applied to the upper surface thereof,
The piezoelectric vibrating plate 16 is laminated, and an adhesive is applied on the upper surface thereof,
The second flexible cable 18 is arranged in layers. Then, the adhesive is applied to the upper surface of the second flexible cable 18 again. Further, the first matching layer 20, the adhesive, the second
The matching layers 22 are stacked in this order to form a stacked body 24, and the stacking process is completed. At this point, the piezoelectric diaphragm 16 has a flat shape as shown in FIG. Similarly, the first and second flexible cables 14 and 18 and the first and second matching layers 20 and 22 also have flat shapes. That is, the laminated body 24 has a flat shape.

Subsequently, a pressure device (not shown) is provided,
The laminated body 24 is pressed down from above by a pressure plate 28 that is vertically movable. The lower surface (pressing surface) of the pressure plate 28 has a substantially semi-cylindrical shape having a convex shape corresponding to the upper surface shape of the backing material 12, and presses the laminate 24 from above the laminate 24 with a uniform predetermined pressure. can do. As a result, the laminated body 24 is curved as shown in FIG. 1 in accordance with the shape of the upper surface of the backing material 12 and the shape of the lower surface of the pressure plate 28, and mutual members are in close contact with each other. At this time, the excess portion of the adhesive applied between the members is extruded from each adhesive layer to form an adhesive layer having an optimum thickness.

Then, the adhesive is cured with the pressure plate 28 pressing the laminate 24. For example, when a thermosetting adhesive is used as the adhesive, it is placed in a thermosetting oven or the like while maintaining the above-mentioned pressed state, and a curing treatment is performed for a predetermined time. After that, when the pressure is released, the ultrasonic transducer 10 having the curved surface is completed.

As described above, by bending the laminate 24 in accordance with the preset curved surface shape of the backing material 12, the ultrasonic beam transmitted and received by the piezoelectric diaphragm 16 is indicated by the arrow in FIG. 2 (a). It becomes possible to focus in the B direction, and the ultrasonic beam can be focused without using an acoustic lens. In addition, the first and second flexible cables 14 and 18 have a sheet shape and can be easily brought into close contact with the front and back surfaces of the piezoelectric vibrating plate 16, and also have electrodes formed on the bending piezoelectric vibrating plate 16. The first and second flexible cables 1
Since the positioning connection with the Nos. 4 and 18 can be performed easily and collectively, the manufacturing becomes easy.

Since focusing can be performed without using an acoustic lens as in the conventional case, the output power is less attenuated with respect to the input power, and the ultrasonic probe can be efficiently driven, and more than necessary. Since the input power of 1 is not required, the temperature rise on the probe surface can be reduced. Further, the same effect can be expected at the time of reception. Further, the direction of the ultrasonic beam can be easily determined according to the shape of the upper surface of the backing material, and the beam characteristics can be easily improved.

In this embodiment, the case where the upper surface of the backing material has a concave shape has been described as an example, but it may have a convex shape if necessary. Further, in this embodiment,
Although an example of forming a plurality of notched grooves to bend the piezoelectric vibrating plate has been described, even if it is completely separated in the direction along the grooves, it is easy to bend and connect with a flexible cable as in the present embodiment. Can be done. Further, after the adhesive is cured in the present embodiment, it is also possible to perform grooving with a dicing saw and divide the array vibration element.

[0038]

According to the present invention, it becomes possible to easily manufacture an ultrasonic vibrator including a piezoelectric vibrating plate having a curved shape, focus an ultrasonic beam without using an acoustic lens, and form a focus. It can be performed.

[Brief description of drawings]

FIG. 1 is a structural conceptual diagram of an ultrasonic vibration manufacturing method and an ultrasonic vibrator according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating a piezoelectric vibrating plate of the ultrasonic vibrator according to the embodiment of the invention.

[Explanation of symbols]

10 Ultrasonic transducer, 12 Backing material, 14 1st
Flexible cable, 16 Piezoelectric diaphragm, 18 2nd
Flexible cable, 20 first matching layer, 22 second
Matching layer, 24 laminated body, 26 notch groove, 28 pressure plate.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-8-280097 (JP, A) JP-A-7-174194 (JP, A) JP-A-63-128899 (JP, A) JP-A-58- 120397 (JP, A) JP 60-114239 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04R 17/00 330 H04R 17/00 332 A61B 8/00 G01N 29 / 24 502

Claims (8)

(57) [Claims] 1. A sheet-shaped first flexible cable which functions as a signal lead thin plate on the upper surface of a hard backing material having an upper surface having a predetermined curvature in a direction orthogonal to the scanning direction of ultrasonic waves, and the scanning direction. A plurality of cutouts parallel to the ultrasonic wave are formed in a direction orthogonal to the scanning direction of the ultrasonic wave, and a piezoelectric vibrating plate having at least one of the front and back surfaces divided, and a sheet-shaped second flexible plate that functions as a ground lead thin plate. A laminating step of sequentially laminating the cable and one or more matching layers to form a laminated body; and applying pressure from above or below the laminated body to form the first laminated body .
For flexible cables and second flexible cables
Therefore, with the piezoelectric diaphragm sandwiched from the front and back,
A method of manufacturing an ultrasonic transducer, comprising: a deforming step of pressing and deforming the laminated body into a shape along the upper surface shape of the backing material. 2. The manufacturing method according to claim 1, wherein in the deforming step, the laminate is pressed and deformed by a pressing plate having a pressing surface having a shape corresponding to an upper surface shape of the backing material. Ultrasonic transducer manufacturing method. 3. The manufacturing method according to claim 1 or 2, wherein between one of the electrodes of the two surfaces of the first flexible cable and the piezoelectric diaphragm, and between the two surfaces of the second flexible cable and the piezoelectric diaphragm. A method for manufacturing an ultrasonic transducer, wherein the connection between the other electrodes is performed simultaneously with the pressing deformation of the laminate. 4. The manufacturing method according to claim 1, further comprising the step of interposing an adhesive between the backing material and the laminate, and between the laminates. And a curing step of curing the adhesive while maintaining the pressed state of the deforming step. 5. The ultrasonic transducer according to claim 4, further comprising a groove forming step of forming a groove in the laminate for dividing into array transducers after the curing step. Manufacturing method. 6. A hard backing material having an upper surface having a predetermined curvature in a direction orthogonal to the scanning direction of ultrasonic waves, and a cut parallel to the scanning direction for curving along the shape of the upper surface of the backing material. A plurality of notch grooves are formed in a direction orthogonal to the scanning direction of ultrasonic waves, and a bendable piezoelectric vibrating plate in which at least one of the front and back surfaces is divided, and a single layer curved along the curved shape of the piezoelectric vibrating plate The above matching layer is included, and the piezoelectric diaphragm is sandwiched between the front and back surfaces of the piezoelectric diaphragm.
As signal lead thin plate and ground lead thin plate
An ultrasonic transducer in which functional sheet-shaped flexible cables are closely arranged. 7. The ultrasonic vibrator according to claim 6, wherein a groove is formed in the piezoelectric vibrating plate and the matching layer to form an arrayed vibrator. 8. The ultrasonic vibrator according to claim 6 , wherein the cutout groove is filled with an adhesive agent having flexibility after being hardened .